<?hh // strict
/**
 * Copyright (c) 2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the "hack" directory of this source tree.
 *
 *
 */

function foo(?int $x): void {
  while (!is_null($x)) {
    $x += 1;
    $x = null;
  }

  $x += 5;
}
